In a steam pipe line of a steam turbine and the like provided in a power generation facility and the like, a main steam valve is provided. The main steam valve is configured to adjust the flow rate of fluid (steam) to be supplied and to stop the supply of the fluid.
The main steam valve is provided with a casing having a flow path of the fluid formed therein and a valve body provided so as to be movable along an axis inside the flow path. In the flow path formed inside the casing, a valve seat is formed that can be closed by the valve body. The valve body moves toward a first side in an axis direction to approach the valve seat, and the valve body moves toward a second side in the axis direction to separate away from the valve seat. This configuration changes a flow path area of a gap between the valve body and the valve seat to adjust the flow rate of the fluid.
Patent Document 1 discloses a main steam valve that is further provided with a strainer housed inside the casing and a shielding plate provided on a side surface of the strainer. On the outer circumferential surface of the strainer, a plurality of minute holes are provided, through which the fluid passes. The fluid, which has flowed in from a main steam inlet, flows along the outer circumferential surface of the strainer, and at the same time, passes through the holes and flows from the outer side toward the inner side of the strainer. Then, the fluid, which has flowed into the inner side of the strainer, flows toward a main steam outlet that is open in a direction that intersects the main steam inlet. Here, as a result of the fluid flowing while curving at an acute angle, a secondary flow is generated, and further, a swirling vortex flow is generated as a result of separate fluid flowing into a velocity defect component of this secondary flow. In response to this, in Patent Document 1, the shielding plate provided on the side surface of the strainer controls the flow of the fluid in the strainer, thereby suppressing the generation of the swirling vortex flow.